Overmolded grasper jaw

ABSTRACT

The invention is directed to a surgical instrument comprising an elongate tube extending along an axis including a camming rod and an actuation mechanism operably connected to the camming rod, the camming rod having a camming pin and a camming projection; a first jaw spine having a first cam slot, a first interior camming surface, and a first exterior camming surface; and a second jaw spine having a second cam slot, a second interior camming surface, and a second exterior camming surface, the second jaw spine pivotally connected to the first jaw spine at a common pivot pin operably connected to the elongate tube to open and close the jaw spines in response to movement of the actuation mechanism. The camming pin rides along the first and second interior camming surfaces and operates to close the jaw spines when the camming rod is moved proximally. When the camming rod moves distally, the camming projection rides on the first and second exterior camming surfaces formed on the proximal sides of the respective first and second jaw spines and operates to open the jaw spines. A feature of the invention is one camming surface on each jaw spine can facilitate closing the jaw spines while the other camming surface on each jaw spine can facilitate opening the jaw spines. These two camming surfaces on each jaw spine can be widely separated. The jaw spines can be formed of a metallic material and are overmolded with an atraumatic plastic material. By overmolding the plastic onto the metal spine, an atraumatic outer surface can be formed of the plastic material along with a high degree of detail.

This is a non-provisional application claiming the priority ofprovisional application Ser. No. 60/519,849, filed on Nov. 12, 2003,entitled “Overmolded Grasper Jaw and Double Camming ActuationMechanism,” which is fully incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to surgical graspers having opposingjaws and, in particular, to composite grasper jaws and mechanisms foractuating the jaws.

2. Discussion of Related Art

In the past, grasper jaws have been formed of metal in order to providestrength and reliability. Various processes of forming the metal haveincluded stamping, EDM (Electrical Discharge Machining), photochemicaletching, water jet cutting, laser cutting, and machining. All of theseprocesses are relatively expensive and time consuming since the jawsmust end up with outer surfaces and edges which are atraumatic to bodytissue. In addition, the actuation mechanisms of the past have typicallyoperated with a single pin moveable axially within two slots, eachassociated with one of the jaws. The two slots have provided fourcamming surfaces to open and close each of the two jaws.

SUMMARY OF THE INVENTION

The present invention is directed to a surgical instrument such as asurgical grasper comprising an elongate tube extending along an axisincluding a camming rod and an actuation mechanism operably connected tothe camming rod, the camming rod having a camming pin and a cammingprojection; a first jaw spine having a first cam slot, a first interiorcamming surface, and a first exterior camming surface; and a second jawspine having a second cam slot, a second interior camming surface, and asecond exterior camming surface, the second jaw spine pivotallyconnected to the first jaw spine at a common pivot pin operablyconnected to the elongate tube to open and close the jaw spines inresponse to movement of the actuation mechanism.

A feature of the invention is the camming pin rides along the first andsecond interior camming surfaces and operates to close the jaw spineswhen the camming rod is moved proximally. With this aspect, the firstexterior camming surface is formed on the proximal side of the first jawspine, the second exterior camming surface is formed on the proximalside of the second jaw spine, and when the camming rod moves distally,the camming projection rides on the first and second exterior cammingsurfaces and operates to open the respective first and second jawspines. In other words, one camming surface on each jaw spine canfacilitate closing the jaw spines while the other camming surface oneach jaw spine can facilitate opening the jaw spines. These two cammingsurfaces on each jaw spine can be widely separated to provide differentmechanical advantages for the opening and closing operations. With thisaspect, the closing camming surfaces can be positioned further from thecommon pivot point to provide an increase mechanical advantage foropening the jaw spines. This is particularly beneficial during asurgical procedure involving the blunt dissection of tissue. Thedifferent mechanical advantages also can be tailored to accommodate thedifferent loads encountered when closing and opening the jaw spines.

The jaw spines can be formed of a metallic material and are overmoldedwith an atraumatic plastic material. The combination of the metal spineand plastic overmold provide a very rigid composite jaw whileaccommodating relatively inexpensive manufacturing technologies. Forexample, the jaw spines do not need to be manufactured with a processdemanding an atraumatic outer surface. By overmolding the plastic ontothe metal spine, an atraumatic outer surface can be formed of theplastic material along with a high degree of detail. Additionally, theovermolded jaws can be provided with features that facilitateapplication of atraumatic pads.

In another aspect, the invention is directed to a surgical instrumentcomprising an elongate tube extending along an axis including anactuation rod; a first jaw spine having a proximal end; a second jawspine having a proximal end, the second jaw spine being pivotallyconnected to the first jaw spine at a common pivot pin operablyconnected to the elongate tube to open and close the jaw spines inresponse to movement of the actuation rod; a first link having a distalend pivotally connected to the proximal end of the second jaw spine anda proximal end pivotally connected to a pivot pin on the actuation rod;and a second link having a distal end pivotally connected to theproximal end of the first jaw spine and a proximal end pivotallyconnected to the pivot pin of the actuation rod.

In another aspect, the surgical instrument of the invention comprises anelongate tube extending along an axis including an actuation rod; afirst jaw spine having a proximal end and a distal end, the proximal endhaving a first series of gear teeth formed around a first hole; a secondjaw spine having a proximal end and a distal end, the proximal endhaving a second series of gear teeth formed around a second hole, thesecond jaw spine being pivotally joined to the first jaw spine by apivot pin through the first and second holes that operably opens andcloses the jaw spines in response to movement of the actuation rod; andthe elongate tube having a first fenestration of windows extendingaxially on one side of the tube and a second fenestration of windowsextending on an opposite side of the tube facing the first fenestrationof windows such that the first series of gear teeth can be positioned toride within the first fenestration of windows and the second series ofgear teeth can be positioned to ride within the second fenestration ofwindow. With this aspect, when the actuation rod is drawn proximallywithin the elongate tube, the first and second series of gear teeth arepivoted on the pivot pin by the respective first and second fenestrationof windows; and when the actuation rod is moved distally relative to theelongate tube, the first and second fenestrations of windows rotate therespective first and second series of gear teeth in opposite directionsto an open position.

In yet another aspect, the invention is directed to a surgicalinstrument comprising an elongate tube extending along an axis includingan actuation rod; a first jaw spine having a first cam slot, the firstjaw spine being coupled to the elongate tube by a first pivot pin; and asecond jaw spine having a second cam slot, the second jaw spine beingcoupled to the elongate tube by a second pivot pin, the second jaw spinebeing connected to the first jaw spine at a common pin attached to theactuation rod that rides within the first and second cam slotsassociated with the respective first and second jaw spines. When theactuation rod is moved distally, the common pin rides within the firstand second cam slots causing the respective first and second jaw spinesto rotate on the respective first and second pivot pins to an openposition. When the actuation rod is pulled proximally relative to theelongate tube, the common pin moves to the proximal ends of the firstand second cam slots causing the jaw spines to pivot on their respectivefirst and second pivot pins to a generally closed position.

In another aspect, the invention is directed to a surgical instrumentcomprising an elongate tube extending along an axis including an outertube and an actuation rod; a first jaw spine having a first cam slot,the first jaw spine being coupled to the outer tube by a first pivot pindisposed in the first cam slot; and a second jaw spine having a secondcam slot, the second jaw spine being coupled to the outer tube by asecond pivot pin disposed in the second cam slot, the second jaw spinebeing pivotally connected to the first jaw spine at a common pinattached to the actuation rod. When the actuation rod is moved distallyrelative to the outer tube, the first and second jaw spines pivot on thecommon pin as the respective first and second pivot pins ride within therespective first and second cam slots causing the first and second jawspines to open.

In yet another aspect, the invention is directed to a surgicalinstrument comprising an elongate tube extending along an axis includingan outer tube and an actuation rod; a first jaw spine having a firstouter surface and a first stub extending outwardly of the first outersurface; and a second jaw spine having a second outer surface and asecond stub extending outwardly of the second surface, the second jawspine being pivotally connected to the first jaw spine by a common pinattached to the outer tube, wherein the actuation rod is bifurcated atits distal end to form two extensions that extend outwardly of the firstand second surfaces, respectively. Each of the two extensions furthercomprises a slot, and the slots traverse one another and to the axis.Each of the slots of the two extensions is sized and configured toreceive their respective first and second stubs associated with therespective first and second jaw spines. When the actuation rod is moveddistally relative to the outer tube, the first and second stubs areforced to the distal end of their respective first and second slotscausing the respective first and second jaw spines to close. When theactuation rod is pulled proximally relative to the outer tube, the firstand second stubs are moved inwardly as they transition to the distal endof the respective first and second slots causing the respective firstand second jaw spines to move to an open position.

These and other features and advantages of the invention will becomemore apparent with the description of the invention and reference to theassociated drawings.

DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included in and constitute a partof this specification, illustrate the embodiments of the invention and,together with the description, explain the features, advantages andprinciples of the invention. In the drawings:

FIG. 1 is a top plan view of a grasper of the invention including asingle pivot pin and a double cam mechanism;

FIG. 2 is a bottom plan view of the grasper jaw of FIG. 1 illustratingin greater detail four camming surfaces associated with the jaws;

FIG. 3 is a perspective view of a grasper jaw in accordance with anotherembodiment of the invention including linkage in an actuation mechanism;

FIG. 4 is a perspective view of an actuation mechanism of a grasper jawin accordance with another embodiment of the invention including a rackand pinion;

FIG. 5 is a perspective view of the actuation mechanism shown in FIG. 4in an open position;

FIG. 6 is a top perspective view of the top jaw of the grasper jaw ofFIG. 4;

FIG. 7 is a bottom perspective view of the bottom jaw of the grasper jawof FIG. 4;

FIG. 8 is a side elevation view of an actuation mechanism of a grasperjaw in accordance with another embodiment of the invention including aseparate pivot for each of the jaws;

FIG. 9 is a top plan view of an actuation mechanism of a grasper jaw inaccordance with another embodiment of the invention having a doublepivot and slotted jaws;

FIG. 10 is a bottom plan view of the grasper jaw of FIG. 9;

FIG. 11 is a top plan view of an actuation mechanism of a grasper jaw inaccordance with another embodiment of the invention including a doublepivot and a double cam;

FIG. 12 is a bottom plan view of the grasper jaw of FIG. 11;

FIG. 13 is a top plan view of an actuation mechanism of a grasper jaw inaccordance with another embodiment of the invention having a reversedslot with a pivot;

FIG. 14 is a bottom plan view of the grasper jaw of FIG. 13;

FIG. 15 is a top plan view of an actuation mechanism of a grasper jaw inaccordance with another embodiment of the invention having a slottedactuation rod; and

FIG. 16 is a bottom plan view of the grasper jaw of FIG. 15.

DESCRIPTION OF THE INVENTION

A surgical grasper is illustrated in FIG. 1 and designated by thereference numeral 10. The grasper is an elongate device having an axis12 which extends between a proximal end 14 and a distal end 16. A pairof opposing jaw spines 18 and 21, disposed at the distal end 16, areoperable between opened and closed positions by an actuation mechanism23. A shaft assembly 25 extends along the axis 12 and includes an outertube 27 and an inner actuation rod 30. The spines 18 and 21 arepivotally attached to the outer tube 27 by a common pivot pin 32.

The actuation mechanism 23 includes a distal camming pin 34 and aproximal camming projection 36. Both the pin 34 and projection 36 arecarried by the actuation rod 30 which is moveable axially within theouter tube 27.

The camming pin 34 rides on two interior camming surfaces 38 and 41 eachof which defines a slot in one of the jaw spines 21 and 18,respectively. When the actuation rod 30 is moved proximally, the cammingpin 34 rides along the camming surfaces 38 and 41 and operates to closethe jaw spines 18 and 21.

The camming projection 36 operates with respect to exterior cammingsurfaces 43 and 45 that are formed on the proximal side of the jawspines 21 and 18, respectively. When the actuation rod 30 is moveddistally, it rides on the exterior camming surfaces 43 and 45, andoperates to open the jaw spines 18 and 21.

Thus, this embodiment includes two pairs of camming surfaces, namely thesurfaces 38 and 41 and the surfaces 43 and 45, which can be disposed atdifferent angles with respect to the axis 12. In this manner, theopening and closing of the jaws can be accomplished with differentmechanical advantages. This enables the actuation mechanism 23 to bestructured so that there is a higher mechanical advantage for closingthe jaws when an increased load is encountered, and a lower mechanicaladvantage for opening the jaws when a higher speed may be desired.

In the embodiment of FIG. 3, elements of structure similar to thosepreviously described are designated with the same reference numeralfollowed by the lower case letter “a.” It can be seen that thisembodiment includes the shaft assembly 25 a, the outer tube 27 a and theactuation rod 30 a, as well as the jaw spines 18 a and 21 a that arepivotally connected on the common pivot pin 32 a. However, in thisembodiment the proximal ends of the jaw spines 18 a and 21 a are coupledto the actuation rod 30 a by a pair of links 50 and 47, respectively.These links 47 and 50 are pivotally connected through a common pivot pin52 to the actuation rod 30 a. At their distal ends, the links 47 and 50are individually connected to the jaw spines 21 a and 18 a,respectively. Thus, the link 47 is coupled to the jaw spine 21 a by apivot pin 54 and the link 50 is coupled to the jaw spine 18 a through apivot pin 56.

In operation, the embodiment of FIG. 3 also functions with the actuationrod 30 a being moved axially relative to the outer tube 27 a. When theactuation rod 30 a is moved distally, the pivot pin 52 approaches thepivot pin 32 a. This causes the distal ends of the links 47 and 50 tospread, resulting in the separation or opening of the jaw spines 18 aand 21 a. When the actuation rod 30 a is pulled proximally relative tothe outer tube 27 a, the pin 52 moves away from the pin 32 a causing thedistal end of the links 47 and 50 to draw inwardly thereby closing thejaw spines 18 a and 21 a.

Referring to FIG. 4, elements of structure similar to those previouslydiscussed will be designated with the same reference numeral followed bythe lower case letter “b.” Thus, this embodiment includes the outer tube27 b, actuation rod 30 b, as well as the jaw spines 18 b and 21 b. Inthis case, the outer tube 27 b is provided with a fenestration ofwindows 58 extending axially on one side of the outer tube 27 b. Asimilar fenestration of windows 61 extends axially on the opposite sideof the outer tube 27 b.

The jaw spines 18 b and 21 b are best illustrated in the perspectiveviews of FIGS. 6 and 7. On the proximal end of the jaw spine 18 b, aseries of gear teeth 63 are centered on a hole 65 that is offset fromthe longitudinal dimension of the jaw spine 18 b. The jaw spine 21 b issimilarly constructed with a plurality of gear teeth 67 centered on ahole 70 that is offset from the longitudinal dimension of the jaw spine21 b.

In operation, the jaw spines 18 b and 21 b are joined by the pivot pin32 b (FIG. 5), which extends through the holes 65 and 70. The pin 32 bcan be further extended into at least one axial slot 72 in the outertube 27 b. This axial slot 72 is positioned between the fenestration ofwindows 58 and the fenestration of windows 61.

With this configuration, the gear teeth 63 of the jaw spine 18 b can bepositioned to ride within the fenestration of windows 58. Similarly, thegear teeth 67 of the jaw spine 21 b can be positioned to ride within thefenestration of windows 61.

As with the previous embodiments, the actuation rod 30 b is movableaxially relative to the outer tube 27 b. This movement is restricted inthis embodiment by the length of the axial slot 72. When the actuationrod 30 b is drawn proximally within the outer tube 27 b, the gear teeth58 and 67 are pivoted on the pin 32 b by the fenestration of windows 58and 61, respectively. With the windows 58 and 61 disposed on oppositesides of the outer tube 27 b, the jaw spines 18 b and 21 b are moved indifferent directions, in this case to a closed position as illustratedin FIG. 4.

When the actuation rod 30 b is moved distally relative to the outer tube27 b, the fenestration of windows 58 and 61 rotate the gear teeth 63 and67, respectively, in opposite directions, in this case, to an openposition as illustrated in FIG. 5.

Another embodiment of the invention is illustrated in the side elevationview of FIG. 8 where elements of structure similar to those previouslydiscussed are designated with the same reference numeral followed by thelower case letter “c.” Thus, in this embodiment the jaw spines aredesignated by the reference numeral 18 c and 21 c, while the outer tubeand actuation rod are designated with the reference numerals 27 c and 30c, respectively. As illustrated in FIG. 8, the jaw spine 18 c ispivotally attached to the outer tube 27 c by a pivot pin 72. Similarly,the jaw spine 21 c is pivotally attached to the outer tube 27 c by apivot pin 74. The jaw spines 18 c and 21 c are also attached to theactuation rod 30 c by a common pivot pin 76.

As in previous embodiments, the device is operated by moving theactuation rod axially relative to the outer tube 27 c. With the commonpivot pin 76 disposed inwardly of the individual pins 72 and 74, theactuation rod 30 c can be pulled proximally relative to the outer tube27 c to close the jaw spines 18 c and 27 c. These jaw spines rotate ontheir individual pins 72 and 74 to a closed position as illustrated inFIG. 8. If the actuation rod 30 c is pushed distally relative to theouter tube 27 c, the jaw spines 18 c and 27 c rotate on their respectivepivot pins 72 and 74 outwardly to an open position.

The embodiment of FIG. 9 contains elements of structure which aresimilar to those previously disclosed. In this case, these elements aredesignated with the same reference numeral followed by the lower caseletter “d.” Thus, this embodiment includes the outer tube 27 d, theactuation rod 30 d and the jaw spines 18 d and 21 d. The jaw spines 18 dand 21 d are coupled to the outer tube 27 d by individual pivot pins 78and 81, respectively. With this embodiment, a common pin 83 is providedthat is attached to the actuation rod 30 d, which rides within a pair ofintersecting slots 85 and 87 associated with the jaw spines 21 d and 18d, respectively.

As in previous embodiments, this device is operated by moving theactuation rod 30 d axially relative to the outer tube 27 d. When theactuation rod 30 d is moved distally, the common pin 83 rides within therespective slots 85 and 87 of the jaws 21 d and 18 d. This causes thejaw spines 18 d and 21 d to rotate on the individual pivot pins 78 and81, respectively, to an open position as illustrated in FIG. 9. When theactuation rod 30 d is pulled proximally relative to the outer tube 27 d,the common pin 83 moves to the proximal ends of the slots 85 and 87.This causes the jaw spines 21 d and 18 d to pivot on their respectivepins 81 and 78 to a generally closed position.

In each of the above embodiments of the invention, the jaw spines suchas jaw spines 18 d and 21 d can be overmolded with plastic to form acomposite structure. In the example shown in FIG. 9, one of thecomposite jaws can be formed with the metal interior jaw spine 18 d andan outer plastic overmold 90. A similar outer plastic overmold 92 can beformed on the metal jaw spine 21 d. As noted, the plastic overmolds 90and 92 can be easily and inexpensively provided with features such as acoupling detent 94 which is adapted to receive an atraumatic jaw pad 96.It is these features which can be easily and inexpensively molded intothe plastic overmold 90 but which would be economically impossible toform on metal jaws. Thus the rigid composite jaw formed of the jaw spine18 d and overmold 90 is not only practical but also cost effective andaccordingly facilitates the application of additional features such asthe disposable atraumatic pads 96.

The embodiment of FIG. 11 is similar to that of FIG. 9 where elements ofstructure similar to those previously discussed are designated with thesame reference numeral followed by the lower case letter “e.” Thus, thisembodiment includes the outer tube 27 e, the actuation rod 30 e, as wellas the jaw spines 18 e, 21 e and associated overmolds 90 e and 92 e,respectively.

This embodiment is similar to that of FIG. 9 in that it includes theindividual pins 78 and 81, as well as the common pin 83. In thisembodiment, however, the common pin 83 is disposed to pivotally connectthe jaw spines 18 e and 21 e with the actuation rod 30 e. In otherwords, the common pin 83 is not disposed in slots, but rather isdisposed in holes associated with the jaw spines 18 e and 21 e. Bycomparison, it will be noted that the individual pins 78 and 81 are notdisposed in holes, as is the case with the embodiment of FIG. 9, butrather are disposed in associated slots.

In operation, as the actuation rod 30 e is moved distally relative tothe outer tube 27 e, the jaw spines 18 e and 21 e pivot on the commonpin 83 e as the individual pins 78 e and 81 e ride within the respectiveslots 101 and 98. This movement causes the jaws 18 e and 21 e to open.Closure of the jaws 18 e and 21 e is achieved by drawing the actuationrod 30 e proximally relative to the outer tube 27 e.

A further embodiment of the invention is illustrated in FIG. 13 whereinelements of structure similar to those previously disclosed aredesignated with the same reference numerals followed by the lower caseletter “f.” Thus, this embodiment includes the outer tube 27 f,actuation rod 30 f, jaw spines 18 f and 21 f, overmolds 90 f and 92 f,as well as the common pivot pin 83 f, and slots 98 f and 101 f. In thiscase, however, the slots 98 f and 101 f intersect so that the individualpins 81 e and 78 e (not shown) in the embodiment of FIG. 11 can becombined into a common pin 103 which is fixed to the outer tube 27 f.With this exception involving the intersecting slots 98 f and 101 f incombination with the common pin 103, the embodiment of FIG. 13 functionsin the same manner as that of FIG. 11.

The embodiment of FIG. 15 contains elements of structure which aresimilar to those previously disclosed. Accordingly, they are designatedwith the same reference numerals followed by the lower case letter “g.”Thus, this embodiment includes the outer tube 27 g, the actuating rod 30g, the jaw spines 18 g and 21 g together with the associated overmolds90 g and 92 g. In this embodiment, the jaw spine 18 g has an outersurface 107 while the jaw spine 21 g has an outer surface 110. A stub112 is fixed, typically by welding, to the jaw spine 18 g and extendsoutwardly of the surface 107. In a similar manner, a separate stub 114can be fixed to the jaw spine 21 g to extend outwardly from the surface110. The jaw spines 18 g and 21 g are overlapped in a scissorsconfiguration and held in a pivotal relationship with the outer tube 27g by a common pin 105.

The actuation rod 30 g is bifurcated at its distal end to form twoextensions 116 and 118 that extend outwardly of the surfaces 107 and110, respectively. These extensions 116 and 118 are provided with slots121 and 123, respectively, which are transversed to the axis 12 g andalso transverse to each other. In this embodiment, the slot 121associated with the extension 116 is sized and configured to receive thestub 112 associated with the jaw spine 18 g. Similarly, the slot 123associated with the extension 118 is sized and configured to receive thestub 114 associated with the jaw spine 21 g.

In operation, the jaw spines 18 g and 21 g pivot about the common pin105 between an open position and a closed position. As the actuating rod30 g is moved distally relative to the outer tube 27 g, the stubs 112and 114 are forced to the distal end of their respective slots 121 and123. This causes the jaw spines 18 g and 21 g to close as they movetoward each other. When the actuating rod 30 g is pulled proximallyrelative to the outer tube 27 g, the stubs 112 and 114 are movedinwardly as they transition to the distal end of the respective slots121 and 123. This causes the associated jaw spines 18 g and 21 g to moveto an open position as they separate. When the actuating rod 30 g ispushed distally relative to the outer tube 27 g, the stubs 112 and 114are moved outwardly as they transition to the proximal end of therespective slots 121 and 123. This causes the associated jaw spines 18 gand 21 g to move to a closed position as they come together.

There are many other embodiments of the invention which are operablewith an actuating rod movable relative to an outer tube. Among theseembodiments will be those which function by moving one of the jawspines, such as the spine 18, with the actuating rod 30 and then movingthe other of the jaw spines, such as the spine 21, with the first spine,such as the spine 18. Various configurations of common pins, individualpins, and slots can be used for these embodiments.

1. A surgical instrument, comprising: an elongate tube extending alongan axis, the elongate tube having a lumen extending along the axisthrough at least a portion of the elongate tube; an actuation rodpositioned within the lumen and adapted to slide longitudinally alongthe axis of the elongate tube; a first jaw spine having a proximal endand a distal end, the proximal end having a first series of gear teethformed around a first hole; a second jaw spine having a proximal end anda distal end, the proximal end having a second series of gear teethformed around a second hole, the second jaw spine being pivotally joinedto the first jaw spine by a pivot pin through the first and second holesthat operably opens and closes the jaw spines in response to movement ofthe actuation rod; and the elongate tube having a first fenestration ofwindows extending axially on one side of the tube and a secondfenestration of windows extending on an opposite side of the tubeopposing the first fenestration of windows such that the first series ofgear teeth can be positioned to ride within the first fenestration ofwindows and the second series of gear teeth can be positioned to ridewithin the second fenestration of windows, the elongate tube furtherhaving an elongate slot formed therein, the elongate slot receiving aportion of the pivot pin.
 2. The surgical instrument of claim 1, furthercomprising an atraumatic plastic overmold over each of the jaw spines.3. The surgical instrument of claim 2, wherein the plastic overmold ismolded with a coupling detent adapted to receive an atraumatic jaw pad.4. The surgical instrument of claim 1, wherein the actuation rod isdrawn proximally within the elongate tube.
 5. The surgical instrument ofclaim 1, wherein when the actuation rod is drawn proximally within theelongate tube, the first and second series of gear teeth are pivoted onthe pivot pin by the respective first and second fenestration ofwindows.
 6. The surgical instrument of claim 1, wherein when theactuation rod is moved distally relative to the elongate tube, the firstand second fenestrations of windows rotate the respective first andsecond series of gear teeth in opposite directions to an open position.7. A surgical instrument, comprising: an elongate tube; an actuation rodlongitudinally slidable within the elongate tube; a first jaw spinehaving a first series of gear teeth; and a second jaw spine having asecond series of gear teeth, the second jaw spine being pivotally joinedto the first jaw spine by a pivot pin that operably opens and closes thejaw spines in response to movement of the actuation rod; and theelongate tube having means for engaging the first and second series ofgear teeth; wherein the means for engaging the first and second seriesof gear teeth comprises windows disposed in the elongate tube; and theelongate tube having an axial slot for engaging the pivot pin.
 8. Thesurgical instrument of claim 7, further comprising an atraumatic plasticovermold over each of the jaw spines.
 9. The surgical instrument ofclaim 7, wherein the actuation rod is movable proximally and distallywithin the elongate tube.
 10. The surgical instrument of claim 9,wherein when the actuation rod is drawn proximally within the elongatetube, the first and second series of gear teeth are pivoted on the pivotpin by the means for engaging the first and second series of gear teeth.11. The surgical instrument of claim 9, wherein when the actuation rodis moved distally relative to the elongate tube, the means for engagingthe first and second series of gear teeth rotate the first and secondseries of gear teeth in opposite directions to an open position.
 12. Asurgical instrument, comprising: an elongate tube having windows and anaxial slot formed therein; a first jaw spine having a first series ofgear teeth arranged to engage the windows; and a second jaw spine, thesecond jaw spine being pivotally joined to the first jaw spine at apivot joint, the first and second jaw spines rotatable in oppositedirections to operably open and close and the pivot joint slidable inthe axial slot relative to the elongate tube, such that a length of theaxial slot defines limits of rotation of the first and second jawspines.
 13. The surgical instrument of claim 12, wherein the elongatetube has a second set of windows and the second jaw spine has a secondseries of gear teeth arranged to engage the second set of windows. 14.The surgical instrument of claim 12, further comprising an atraumaticplastic overmold over each of the jaw spines, one of the jaw spinesbeing metallic.